U.S. Coast Guard Machinery Technician 3rd Class Michael Stefanski, CGC Buckthorn, measures the thickness in the links of the chain while underway on the St. Marys River, June 8, 2022. If a chain is too thin from wear, the link is replaced before the buoy is repositioned in the water. (U.S. Coast Guard photo by Petty Officer 3rd Class Gregory Schell)